It is known that the quality of sleep has a significant effect on the quality of life. Multiple clinical studies have correlated poor sleep quality with hypertension, obesity, stroke and diabetes. It is also known that mattresses can significantly affect sleep quality.
All existing consumer mattresses impart sleep-disturbing side-lying interface pressures to the body. Mattress-induced discomfort caused by excessive body pressures and postural misalignment result in increased tossing and turning causing sleep disruption and reduced sleep quality. An ideal mattress must have the support and resiliency over the length of the body to support the body in postural alignment while also providing ultra-low body pressures on all parts of the body in contact with the mattress to reduce mattress pressure-induced sleep disturbance.
The object of this invention is to eliminate mattress-induced sleep quality degradation. The present invention is the result of many years of university sleep research and development. The construction of over 100 prototypes was required to solve the heretofore unsolved equation of providing ultra-low pressures with optimal postural alignment.
Ultra-low mattress body interface pressure can be defined as at or below 0.6 PSI (32 mmHg), medically known as the ischemic pressure threshold. This interface pressure between the mattress and body allow the capillaries of the skin to remain open thereby greatly reducing or eliminating the incidence of pressure-induced sleep-disrupting movement. This pressure, if unrelieved, would eventually cause a decubitus ulcer (bed sore) to form.
Side sleeping is the most common and desired sleep position. Most existing consumer mattresses achieve back-lying body pressures on most, but not all parts of the body, of 0.6 PSI. If the back-lying area is about 900 square inches, that is usually sufficient area to maintain low pressures on most parts of the body. But the same side-lying body only presents about 500 square inches of contact area which, under the same load, significantly increases the unit area pressure to higher than 0.6 PSI on some parts of the body, notably the shoulder and hip areas, also known as bony prominences.
Achieving 0.6 psi or below on all body areas, including the shoulder and hip areas, when side-lying on static conventional mattresses—without certain mattress structural modifications—cannot be achieved with current materials. Prototypes leading to the present invention have achieved side-lying pressures on the shoulder and hip—as well as the rest of the body—of significantly less than 0.6 psi.
Since a recumbent body has both varying density and contour in the longitudinal direction, the ideal mattress must conform (deflect) to these variations in order to achieve correct postural alignment. The deflection parameters of the mattress must vary along its length to match the varying body density and contours while maintaining interface pressures at or below 0.6 PSI.
New foam mattresses and toppers by the inventor using foam deflection are disclosed in international application no. WO 2016/023109 A1 (Torbet) wherein the top portion of the mattresses comprises a plurality of displacement tunnels at different body part areas, such as shoulders or hip area, allowing the body part area foam above the tunnel to displace downward to provide pressure reduction and alignment for the body part such as shoulders or hip. Although the invention disclosed in this international application is pretty efficient, there is place for improvement in the shape, number and location of the channels for improving or modulating pressure reduction, alignment and comfort.